Fos/Jun Family

The AP-1 transcription factor is mainly composed of Jun (c-Jun, JunB, JunD), Fos (c-Fos, FosB, Fra-1, Fra-2) and ATF (ATFa, ATF-2, ATF-3) protein dimers. All contain the bZIP basic DNA-binding leucine zipper domain. Jun, but not Fos, proteins can homodimerize. AP-1 mediates gene regulation in response to cytokines, growth factors, stress signals, bacterial and viral infections, oncogenic stimuli and other physiological and pathological stimuli.